Events

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Wednesday,20,08,2025

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8
2025

13 / 8 / 2025

Seminar

Joint Seminar: “Beyond Closed Wave Systems: Non-Hermiticity, Nonlinearity, and Casimir Effect” by Prof. Kun DING | Wednesday, August 20, 2025, 11:00am CYMP522

The classical wave system has demonstrated itself as an excellent platform to realize and investigate novel phenomena and physics. The bedrock principle is to utilize the macroscopic quantities obtained from the homogenization or mean-field treatment. However, it usually deals with Hermitian problems and averages out fluctuations. Therefore, the presentation will cover two topics: non-Hermitian physics and Casimir effect. The first part focuses on the impact of non Hermitian ingredients on soliton formation and dynamics. By constructing a soliton phase diagram, two distinct soliton phases and their transitions are identified. A Wannier-function-based nonlinear Hamiltonian shows that soliton formation critically depends on how skin-mode localization and band nonreciprocity suppress or enhance wave dispersion. Both soliton phases have been demonstrated to be dynamically accessible from bulk and edge excitations. The second part discusses the influence of the metal’s surface electrons on Casimir forces. A three-dimensional frame transformation method has been established by embedding mesoscopic boundary conditions of electromagnetic fields. We find that mesoscopic Casimir forces are sensitive to the surface electron behavior, including spill-in and spill-out, as verified by the multiple scattering method and proximity force approximation. The mechanism has finally been revealed as Casimir softening distances rooted in quantum surface responses of electrons.

Prof. Kun DING

Monday,04,08,2025

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2
2025

27 / 2 / 2025

Conference

AQIS’25 25th Asian Quantum Information Science Conference | 4th -8th August 2025

QIS’25 Asian Quantum Information Science Conference Date: August 4 to August 8, 2025 Venue : Grand Hall of the Lee Shau Kee Lecture Centre, Centennial Campus, the University of Hong Kong (HKU) Hosted by: Quantum Information and Computation Initiative (QICI) of the HKU School of Computing and Data Science HK Institute of Quantum Science & Technology (HKIQST) The AQIS’25 conference will focus on quantum information processing, communication, and cryptography, bridging the fields of quantum physics, computer science, mathematics, and information technologies. As the natural successor of EQIS’01-EQIS’05 and AQIS’06-AQIS’24, AQIS’25 will feature invited talks, selected oral and poster presentations, as well as other activities. Conference Topics Include: Quantum computation and simulation, algorithms, and complexity Quantum information theory Concepts, methods, and tools against decoherence Quantum cryptography Quantum communications experiments and theory Quantum metrology Quantum technologies (optics, NMR, solid state, etc.) Quantum circuit, computer design, and architecture Quantum programming languages and semantics Important Dates: Talk Submission Deadline: April 25, 2025 Poster-only Submission Deadline: May 16, 2025 Notification of Acceptance: May 30, 2025 Final Manuscript Deadline: June 30, 2025 Early Registration Deadline: June 30, 2025 (all deadlines are until 23:59 anywhere on Earth) Invited Speakers: Rotem Arnon-Friedman (Weizman Institute of Science) Warit Asavanant (University of Tokyo) Debbie Leung (University of Waterloo) Chaoyang Lu (University of Science and Technology of China) Chiao-Hsuan Wang (National Taiwan University) Additional speakers to be announced… Sponsors: HKU School of Computing and Data Science HK Institute of Quantum Science & Technology (HKIQST) QICI Join us at AQIS’25 for a deep dive into the exciting world of quantum information and computation! The webpage address of AQIS 2025 http ://aqis-conf.org/2025/

Monday,16,06,2025

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6
2025

3 / 6 / 2025

Seminar

CTCP Seminar: “Authentication of Classical Channels in Quantum Key Distribution” by Prof. Liujun WANG | Monday, June 16, 2025, 3:00pm CYMP522

Quantum Key Distribution (QKD) offers information-theoretic security but relies critically on authenticated classical channels for post-processing steps (e.g., basis sifting and key reconciliation). Without authentication, these channels are vulnerable to man-in-the-middle attacks. Traditional methods require Alice and Bob to pre-share symmetric keys via physical meetings—a solution incompatible with multi-user QKD networks. We experimentally demonstrate a practical solution using post-quantum signature algorithms to authenticate QKD classical channels. This approach was validated under multiple QKD network topologies in laboratory environments and a real-world metropolitan QKD network operating continuously for 36 days. Our implementation provides quantum-resistant security while uniquely requiring only short-term security (e.g., ~1 second during authentication), contrasting with long-term security assumptions for post-quantum encryption. Additionally, we propose a quantum-teleportation-based protocol for message authentication that simultaneously ensures confidentiality—enabling secure key reconciliation in QKD.